On December 18, 1995, at 1500 eastern standard time, a Hiller 12C, N234SM, touched down hard during a practice autorotation at the Grand Strand Airport in North Myrtle Beach, South Carolina. The instructional flight operated under the provisions of 14 CFR Part 91 with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The helicopter sustained substantial damage; the certified flight instructor and the private pilot were not injured. The flight departed North Myrtle Beach, at 1430. The pilots were conducting pre-checkride flight training. According to the private pilot, they were executing a practice autorotation to a powered recovery. As the pilots maneuvered the helicopter during the flare, the tail rotor assembly struck the ground. No mechanical problems with the airplane were reported by the pilot.